Rotating electrical machine, in particular alternator for motor vehicle

ABSTRACT

The invention relates to a rotary electric machine comprising a rear bearing ( 2 ), an arrangement ( 1 ) for rectifying the current produced by the machine, which comprises a number of positive diodes ( 8 ) supported by a heat dissipater in the overall form of a plate ( 9 ) and a number of negative diodes ( 10 ) supported by support means in the form of a plate advantageously forming part of the rear bearing, the plate ( 9 ) supporting the positive diodes ( 8 ) comprising a great many cooling ribs which have the shape of fins ( 18, 19 ) extending practically radially across the plate, while an opening ( 20 ) for the passage of cooling air is made between each pair of adjacent fins ( 18, 19 ), some fins ( 18 ) extending practically as far as the outer periphery of the support plate ( 9 ).

FIELD OF THE INVENTION

The invention relates to a rotary electric machine, particularly a motorvehicle alternator, of the type comprising a front bearing and a rearbearing on which stator windings are fixed and in which a rotor shaft ismounted so that it can rotate, a rectifier arrangement comprising anumber of positive diodes supported by a heat dissipater in the overallform of a support plate and a number of negative diodes supported by asupport element in the form of a plate, these plates being axiallyjuxtaposed and fixed to the rear bearing, and a device affording coolingby circulating an axial stream of a cooling fluid, such as air, throughaxial openings in said plates, at least some openings in the platesupporting the positive diodes being provided with cooling ribs.Advantageously, the plate supporting the negative diodes forms part ofthe rear bearing.

PRIOR ART

An electric machine of this type is described in document DE-A-19705228.The openings which are made in the plate supporting the positive diodescomprise five openings of significant angular aperture two of which havea trapezoidal overall shape. These trapezoidal openings are eachsurrounded by a rib projecting axially from the plate.

This cooling device with axial openings admittedly affords moreeffective cooling than cooling devices without axial openings, but isstill not satisfactory.

The same is true of the cooling device described in document U.S. Pat.No. 5,646,838.

In that document, the plate supporting the positive diodes comprises agreat many ribs which have the shape of fins extending practicallyradially across the plate; an opening for the passage of cooling airbeing provided between each pair of adjacent fins. The fins extend fromthe inner edge of the support plate and some distance from the outerperiphery of the plate and from the positive diodes; the plate beingthicker in the region of the fins.

SUBJECT OF THE INVENTION

The object of the invention is to improve the cooling of a rotarymachine of the abovementioned type.

To achieve this objective, the machine of the invention is characterizedin that first fins extend practically as far as the outer periphery ofthe plate supporting the positive diodes so that the plate is cooledacross its entire radial stretch.

According to another feature of the invention, at least two positivediodes are arranged near the outer periphery of the plate supporting thepositive diodes and second fins extend as far as said diodes and closeto them. By virtue of this arrangement, the openings can be formedradially under the diodes and the thickness of the plate can beincreased at the diodes to allow better cooling of these diodes.Furthermore, the second fins participate in the cooling.

According to yet another feature of the invention, the openings in theplate supporting the positive diodes constitute, with the fins whichdelimit them, channels for the accelerated flow of cooling air.

Advantageously, at least a first fin is near a positive diode in orderto cool the latter even better still.

Advantageously, the rotary electric machine comprises a cover partwhich, in the region of the fins of the plate supporting the positivediodes, has radial openings corresponding to those of the platesupporting the positive diodes.

These openings are delimited by strips of material or narrow radialribs. The thickness of these ribs is dependent on the thickness of thefins, the ribs being arranged under the fins. This yields communicationbetween the openings of cover and those of the plate supporting thepositive diodes.

The openings of the cover have a greater radial span than those of theplate supporting the positive diodes.

Advantageously, the openings in the cover are split into two by a stripof material or coaxial, that is to say circumferential, ribs. A firstpart of the openings in the cover faces the passage openings in theplate supporting the positive diodes, the second part of the openingsbeing located at the outer periphery of the cover.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood and other objects, features,details and advantages thereof will become more clearly apparent fromthe explanatory description which will follow, given with reference tothe attached schematic drawings which are given solely by way of exampleillustrating one embodiment of the invention and in which:

FIG. 1 is a perspective view of a known rectifier arrangement mounted onthe rear bearing of a motor vehicle alternator;

FIG. 2 is an axial view of the inner face of the bearing according toFIG. 1;

FIG. 3 is a view in axial section of a rotary electric machine in theform of an alternator equipped with a rectifier arrangement according tothe invention;

FIG. 4 is a partial perspective view of the rectifier arrangement ofFIG. 3, without the cover;

FIG. 5 is a perspective view of a heat dissipater of the rectifierarrangement according to FIG. 4;

FIG. 6 is a view from above of the dissipater according to FIG. 5;

FIG. 7 is a view from above of an insulating intermediate plate of therectifier arrangement according to FIG. 4;

FIG. 8 is a perspective view of a protective cover intended to fit overthe rectifier arrangement according to FIG. 4, and

FIG. 9 is a perspective view of an alternator rear bearing, with abuilt-in protective cover, according to another embodiment of theinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

To make the invention and the context in which it falls easier tounderstand, the conventional overall structure of a rectifierarrangement and its arrangement in a multi-phase alternator for a motorvehicle of the type described, for example, in document EP-B-0515259(U.S. Pat. No. 5,270,605) to which reference can be made for greaterdetail will first of all be described, with reference to FIGS. 1 and 2.

As FIG. 1 shows, a rectifier arrangement denoted by the referencenumeral 1 is fixed on the rear bearing 16 of the alternator. This rearbearing carries, in the alternator, together with an appropriate frontbearing, the rotor shaft and the stator of the alternator. Thesebearings belong to a fixed support housing of the alternator intended tobe fixed to a fixed part of the motor vehicle. It is for that reasonthat the bearing 16 has a lug. These bearings are electricallyconducting, conventionally based on aluminum and connected to ground.The stator comprises a stator body in which the stator windings arefixed, the outputs of which windings are connected to the rectifierarrangement described hereinafter. The rear bearing 16 has the overallform of a cup comprising a part forming central dish 3 orientedtransversely and an outer annular rim 4 directed axially and comprisinglateral openings 5 for the outlet of the cooling air drawn in by aninternal fan associated with the rotor of the alternator and visible inFIG. 3.

The bearing 16 comprises a central cylindrical core 6 for housing, via aball bearing, the rotor shaft. The dish 3 is provided around the core 6with air inlet openings 7 intended for the passage of the air used tocool the alternator.

The rectifier arrangement comprises three pairs of positive and negativediodes, a positive diode being duplicated. The diodes are of the typehaving cylindrical bodies constituting one connection terminal, whilethe second terminal consists of a tail extending axially from this body.To reduce the axial bulk, the positive and negative diodes are mountedtop to toe, the tails of the positive diodes entering the openings 7.The positive diodes shown as 8 are forcibly inserted via theircylindrical body into a heat-dissipating support in the overall form ofa plate 9. The negative diodes 10 are forcibly inserted via theircylindrical body into the annular region of the dish 3 of the rearbearing 16, which surrounds the portion comprising the aforesaidopenings 7. The tails, denoted by 111, of the negative diodes passthrough holes 111′ made in the plate 9 supporting the positive diodes 8.This plate 9 is separated from the dish 3 of the bearing 16 by a body inthe overall form of a plate 13 made of an electrically insulatingmaterial, overmolded over a collection of flat conductors. This plate 13is known as a connector and, by virtue of its flat conductors, formswith the positive and negative diodes a rectifier bridge for rectifyingthe current at the output of the stator windings. These windings aredesigned to form the stator phases and comprise electric conductorsconnected to the plate 13. Thus, the reference numeral 114 denotes thewire gripper elements for the passage of these conductors intended toconnect the phases and the neutral of the three-phase stator of thealternator to the rectifier arrangement. The plate 9 supporting thepositive diodes 8 and the intermediate insulating plate 13 are axiallyjuxtaposed and fixed with electrical insulation by screws 115 to thebearing 16. To complete the description, reference numerals 116 and 117respectively denote the electronic regulating device of the alternatorand the output terminal of the alternator which is connected to thedissipating support 9 and to the motor vehicle on-board network, and tothe positive terminal of the battery. The plate 9 is made of a metal. Ofcourse, a plastic cover covers the rectifier arrangement 1. This coveris designed to allow air to circulate while at the same time being fixedto the rear bearing. Such a cover can be seen in FIGS. 3 and 8 and isalso in the form of a cup.

The constructional measures proposed, according to the invention, tooptimize the cooling of the rectifier arrangement will be describedhereinafter with reference to FIGS. 3 to 9. The same references will beused for elements which are identical or similar to those shown in FIGS.1 and 2. The rectifier arrangement 1 according to the inventionadvantageously applies to motor vehicle alternators or to electricmachines of the “alternator/starter motor” type known per se, which areable to operate alternately as an electric motor, particularly a startermotor, or as an alternator. For greater detail, reference can be made toapplication FR-0003131 filed on Mar. 10, 2000 and published under thenumber FR-A-2 806 223 or to document WO 01/69762. Thisalternator/starter motor has the structure of the conventionalalternator and has means, advantageously of the magnetic type, forfollowing the rotation of the rotor to inject current into the statorcoil at the desired time when the machine operates in starter motormode.

FIG. 3 depicts a compact alternator 10 with internal fans 102, 104 andequipped with a rectifier arrangement according to the invention.

This alternator, here of the multi-phase type, consists mainly of asupport casing made in two portions 16, 18 which are perforated so thatair can circulate. The casing internally bears two main components whichare the stator 12 and the rotor 13 as described, for example, indocument U.S. Pat. No. 527,605 (EP B 0 515 259) to which reference canbe made for further details.

The stator 12 surrounds the rotor 13 which is secured to a shaft 15 tothe rear end of which are fixed two slip rings 17, while a pulley (notreferenced) is secured to the front end of the shaft 15. This pulley isintended to receive a belt forming part of a transmission driven by theinternal combustion engine of the motor vehicle. The axis X-Xconstitutes the axis of the shaft 15 and the axis of axial symmetry ofthe alternator.

The stator 12 is made up of a body 19 which in this instance consistsmainly of an axial stack of transverse soft iron laminations. In a wayknown per se, laminations of the stator 12 each comprise notches to formslots which in this instance are axial. These notches open at the innerperiphery of the body 19 which is of cylindrical shape.

The notches extend radially toward the outside and accommodateelectrically conducting axial strands of a rotor coil 23. The groovesare semi-closed on the inside as visible, for example, in document FR A2 603 429.

The electric coil 23 is, for each phase of the alternator, made up forexample of a spiral winding of an electrically conducting wire, in thiscase a copper wire, which is coated with at least one layer ofelectrically insulating material, for example a polyester in two layers,one of the polyimide type and the other of the polyamide imide type.

An electric [sic] insulating sheet is inserted in each notch of the body19 of the stator 12 between the electric coil 23 and the body 19 of thestator 12.

This insulating sheet is immobilized [lacuna] as described in documentWO 02/29958 to reduce noise and the sound levels emitted by thealternator 10, [lacuna] makes it possible to reduce or eliminate therisk of short-circuit between the coil 23 and the body 19.

Because of the winding of the electrically conducting wire, the coil 23therefore in each notch of the body 19 of the stator 12 comprises abundle of electrically conducting elements which pass axially throughthe notches of the body 19 and are extended outside of the body 19 byjoining strands which form lead-outs 39 projecting from each side ofthis body 19 as shown in FIG. 3.

As an alternative, recourse is had to pins of circular or rectangularcross section mounted in the notches forming the axial grooves of thestator 12 as described in document WO-92/06527. As an alternative, fourelectrically conducting elements, such as pins of rectangular sectionand U-shape are mounted radially in superposition per notch as describedin document FR-A-2 819 117. In all cases, the stator 12 has windingsconstituting the coil 23. These stator windings are fixed on theportions 16, 18 described hereinafter.

The inductor rotor 13 is, in this instance, a claw-pole rotor of theLundell type which consists of a cylindrical electric coil 62 mountedbetween the two metal dishes 64 and 66 each comprising claws 68 and 70respectively, which extend axially toward the other dish 66 and 64. Eachplate-claw assembly constitutes a pole wheel, in this instance made ofmagnetic steel. A core 67, in this instance also made of magnetic steel,is inserted axially between the dishes 66, 64 to carry the coil 62. Thecore 67 is of annular shape oriented axially and in this instance is inthe form of a thick washer. This core 67 is separate from the polewheels in order to facilitate the winding of the electrically conductingelement onto the core 67 without the claws 68, 70 constituting animpediment. Each pole wheel is fixed to the shaft 15 via knurled partsof the shaft, one of the which serves to attach the core 67. The claws68 and 70 are angularly offset from one another so that a claw 68 of thedish 64 is inserted between two adjacent claws 70 of the dish 66, andvice versa. The claws have chamfers (not referenced) to reduce themagnetic noise as in document EP-B-0 515 259.

The alternator in this instance has internal ventilation, each dish 64,66 carrying a fan 102, 104 respectively, adjacent to the portion 16, 18of the casing concerned. Each portion 16, 18 of the casing 12 isperforated so that air can circulate and centrally bears a bearing inthe form of a ball bearing 105, 106 respectively, to support the frontend and rear end of the shaft 15, respectively. Thus, one 18, of theseportions 16, 18 is known as the front bearing (the one adjacent to thepulley) and the other 16, is known as the rear bearing. It will be notedthat this pulley is fixed by a nut onto the threaded front end of theshaft 15. In the upper part of FIG. 3, a spacer piece of angle bracketcross section is inserted between the inner race of the bearing 105 andthe pulley. In the lower part of this FIG. 3, the spacer piece isincorporated into the pulley, making it possible to reduce the axialbulk still further.

The bearings 16, 18 have a hollow shape and each have a closed end inthe form of a dish oriented transversely to the axis X-X of thealternator and, at their outer periphery, an axially directed annularrim each having its own machined annular radial end face 26, 28,delimiting a joining plane. The bearings are connected to each other byfixing screws 29.

Each axially directed rim is connected at its other axial end to thetransversely oriented dish which centrally bears the relevant ballbearing 105, 106. In a known way, each dish and each rim respectivelyhave air inlet openings and air outlet openings for the air circulation.FIG. 3 shows some of the air inlet openings made in the dishes of thebearings 16, 18, particularly the openings 7 made in the dish 3 of therear bearing 16, and dotted line has been used to depict two air outletopenings, of the type of the opening 4 of FIG. 1, in the peripheral rimsof the bearings 16, 18.

The air outlet openings in the rims are located facing the lead-outs 39.

The fans 102, 104 are located radially under the lead-outs 39 beingfixed, for example by spot welding, to the dish 64 and the dish 66respectively. These fans 102, 104, secured to the rotor 13, have bladesadvantageously distributed unevenly so as to reduce noise, and in thisinstance are of the centrifugal type. Air is thus drawn in and passesthrough the openings in the dishes to be delivered through the openings,in this instance of oblong shape, in the peripheral rims.

The fans may comprise two series of blades as described in document FR0008549 filed on Jun. 30, 2000 and published under the number FR-A-2 811156.

More specifically, the second series of blades is shorter than the firstseries of blades and at least one second blade is inserted between twoconsecutive blades of the first series of blades.

For further details reference can be made to that document. All thealternative forms in that document being conceivable. [sic] Thus, acover may cover the first series of blades.

The lead-outs 39 are therefore well cooled as is the rectifierarrangement 1, the voltage regulator 116 that the alternator 10 has andthe ball bearings 105, 106.

The rear bearing 16 bears a rectifier arrangement 1 which rectifies theAC current produced by the coil 23 of the stator 12, in this instancethree-phase, and a brush holder collaborating with the slip rings 17. Byvirtue of the arrangement 1, the AC current produced by the coil 23 isconverted into DC current to recharge the vehicle battery and power theconsumers, such as the lighting device, the climate control device, etc.

In the known way, the slip rings 17 are connected to the ends of theexcitation coil 62 of the rotor 13 by wire connections passing behindthe fan 104, as visible in this FIG. 3. When the coil 62 is activated,magnetic poles are formed at the claws 68, 70 in the known way.

Also provided is a protective cover 27, perforated in the way describedhereinafter so that air can circulate.

This cover 27, in this instance made of plastic, covers the brushholder, connected in a known way to the voltage regulator 116, and therectifier arrangement provided with diodes.

The brushes of the brush holder collaborate in rubbing against the rings17. The regulator device allows the voltage supplied by the stator to belimited in order in particular to protect the battery.

The bearings 16, 18 have lugs to fix them to a fixed part of the vehicleand they are connected together by a fastening in this instance usingscrews one of which can be seen in FIG. 3. The vehicle alternator istherefore electrically connected to ground via its bearings 16, 18.

As an alternative, the dishes of the bearings are axially inclined.

As an alternative, the fan 102 is omitted in the knowledge that the rearfan is more powerful.

In general, the alternator comprises at least one internal fan 13secured to the rotor and installed inside the casing underneath alead-out 39 in such a way that the coil 23 is well cooled and that thealternator is of high power while at the same time being compactparticularly in axial terms and not very noisy.

As an alternative, a single fan is installed on the outside at thepulley.

The invention relates in particular to the embodiment of the plate 9forming a support for the positive diodes 8 and constituting adissipater of heat. According to one feature, this plate 9 is arrangedto provide better dissipation of heat and will be known as a heatdissipater. As can be seen in FIGS. 4 to 6, the rectifier arrangementaccording to the invention may confine itself to three positive diodes8, because of the optimization of the cooling afforded by the invention.Unlike in FIG. 1, two of these diodes 8 are arranged near the outerperiphery of the plate, practically on the same circle as the holes 111′of the tails 111 of the negative diodes and the screws 115 that fix therectifier arrangement to the rear bearing. The third diode is arrangednear the terminal 117, known as the positive terminal. Morespecifically, the plate has an extension near the terminal 117, forfixing it to the dish 3.

The holes into which the diodes are forcibly inserted bearing thereference 8′ and the holes for the passage of the screws 115 are markedas 115′. As can be seen clearly in the figures, the central part of thedissipater 9 is therefore clear.

The upper face of the dissipater 9 bears a multitude of fins 118, 119which project at right angles to the face of the plate and extendpractically radially from the radial inner edge of the plate, the fins118, known as first fins, extending, according to one feature of theinvention, practically as far as the outer periphery of the dissipatingplate, the other fins 119, known as second fins, extending as far as theholes that accommodate the diodes, the fixing screws and through whichthe tails of the negative diodes pass.

Here, some of the second fins 119, shorter than the first fins 118,extend according to the invention up close to the positive diodes 8arranged at the outer periphery plate 9 for good cooling of the latter.Other second fins 19 extend up close to the fixing screws 115.

It can be seen that the central positive diode 8 is situated between twolong fins 118, shaped at their outer periphery to surround the centraldiode 8 as closely as possible and that one of the long fins 118 is nearthe other two diodes 8. The fins 118 associated with the centralpositive diode 8 are curved at their outer periphery, one of them towardthe other in order better to surround this central diode. In the exampledepicted, twelve fins 118, 119 are provided on the plate-shapeddissipater 9. Fins are provided on both sides of the plate. FIG. 5reveals that some fins are wider so as to increase the mass of the plate9.

More specifically, to allow an even better removal of heat, theunderside, facing toward the dish 3 of the plate 9 is provided with longfins 1119′[sic] and short fins 118′ like the upper face. Some of thefins 119′, 118′ are very wide.

As shown clearly in the figures, the plate is pierced between the finsin the area available. These openings 120 constitute, with the inwardlyconverging radial fins 118, 119, axial cooling channels which ensureaccelerated flow of cooling air drawn in via the internal fan and thendelivered through the lateral openings 5 in the bearing.

FIG. 7 illustrates the intermediate insulating plate 13 which, in theway corresponding to the plate 9 supporting the positive diodes, hasholes 122 for the passage of the tails of the positive diodes 8, holes123 for the passage of the fixing screws 115, and holes 124 for thepassage of the tails for the passage [sic] of the negative diodes 10,all in the outer annular region near its periphery, the annular part 125situated further in being provided with wide openings 126 for the flowof the cooling air and the arrangement of which corresponds to theopenings 120 of the plate 8. In the context of the invention it could beconceivable for this annular part 125 of the insulating plate to bedispensed with, thus making it possible to reduce the size of the plate13.

In a known way, the heads of the screws 115 bear against the end of ahousing belonging to the plate 113, to clamp the plate 9 into contactwith the plate 113.

FIG. 8 shows a protective cover 27 in the form of a cup intended to capthe rectifier arrangement according to the invention, which differsthrough its optimized configuration, perfectly suited to the dissipaterbecause its part situated above the latter is highly perforated leavingonly narrow radial ribs 128 and one, also narrow, coaxial rib 129. Thelarge openings 130 thus obtained, which extend radially like the coolingfins 119, 118, ensure purely axial accelerated flow of the cooling airdrawn in and thus optimum cooling of the rectifier arrangement of thealternator according to the invention. It will be noted that it is onlythe part forming the transversely oriented central dished part of thecover 27 which has the openings, the axially oriented annular rim of thecover, connected to the outer periphery of the central dish, having noopenings. The air therefore passes axially through the opening 130 and120 in the knowledge that the openings 120 face the openings 7 of therear bearing.

It will the noted that the thickness of the ribs, or radial strip ofmaterial 128, is dependent on the thickness of the fins 118, 119, inthis instance being generally equal thereto. The ribs 128 face the fins118, 119.

Here, the rib or strip of material 129 is circularly continuous whichmeans that the openings 130 are divided into two. A first part of theopenings 130 faces the openings 120 of the plate 9, each advantageouslyhaving a radial length or height greater than that of an opening 120.The rib 129 extends over the openings 120 so that the second part of theopenings 130 faces, in particular, the two positive diodes 8 installedat the outer periphery of the plate 9.

The plate 9 is thus well cooled and the cover 27 is stronger. In a knownway, the cover 27 is fixed by clip-fastening onto the screws 115 whichare provided for that purpose with a threaded part as described indocument WO01/69762.

The axially directed annular rim of the cover 27 here has no openings.

FIG. 9 illustrates an integrated version 132 of the assembly formed bythe rear bearing and the cover protecting the rectifier arrangement,with axial flow openings 132 in the part covering the dissipater of therectifier arrangement which is fixed inside the assembly. In this case,the negative diodes are mounted on a plate which has the configurationof the dish 3 of FIG. 1. This plate is fixed to the rear bearing by anymeans, in the knowledge that this rear bearing 16 is connected toground. The cover 132 therefore advantageously has additionalthicknesses in the form of ribs starting from a tubular portionprojecting out axially with respect to the central part of the coverconstituting the closed end of the rear bearing. These ribs areconnected at their free end to fixing shafts. Thus, the alternator can,by means of its rotor shaft, drive a vacuum pump. For simplicity, theribs, the tubular portion and the fixing shafts have not beenreferenced.

In all cases, the rectifier arrangement comprises a dissipater 9 in theform of a holed plate with radial fins, a plate 13 with connectors and athird constituting the support for the negative diodes, which is formedby the rear bearing or a plate secured to the rear bearing. Recourse istherefore had to three main parts unlike in the embodiment described inthe aforementioned document DE-A-19705228 in which the connector ismounted over the plate bearing the positive diodes and impedesventilation. In the present invention, the connector 13 [lacuna]inserted between the dissipation 9 and the dish 3 of the rear bearing ora plate secured thereto. Radial channels are formed between the fins.The tails of the positive diodes are directed toward the support of thenegative diodes. Two or fewer of the positive diodes extend over theopenings 120.

It is apparent from the description of the invention which has just beengiven that, by virtue of the radial fins and of the openings madebetween these, of the dissipater supporting the positive diodes,accelerated and therefore optimized flow of the cooling air is obtained,the openings made facing each other in the bearing and in the insulatingplate forming a connector contributing to this. Given that the positivediodes are arranged near the outer periphery of the support plate, theconnector may have a small size. It must be noted that all the openingsare configured in such a way that they reduce pressure drops byfacilitating air flow. It must also be emphasized that the openings inthe cover are aligned with the fins of the dissipater supporting thepositive diodes.

The fact that the fins 118, 119 converge toward the inside allows theflow of the cooling fluid, in this instance air but, as an alternativesome other fluid, to be accelerated. The device of two of the positivediodes at the outer periphery of the dissipater 9 makes it possible toincrease the thickness of the dissipater 9 at this point, by creating onthe latter, for example, an additional thickness of trapezoidal overallcross section. Thus the heat is better removed and the plate 9 isstiffened. Advantageously, the dissipation 9 is obtained by molding,based on aluminum.

It will be noted that the references 46, 50, 34 of FIG. 3 respectivelydenote a flat annular seal, thermally conducting resin and pads asdescribed in document WO02/29958.

The seal 46 is inserted axially between the body 19 and an unreferencedshoulder of the rim of the front bearing 18.

The resin is inserted radially between the inner periphery of the rim ofthe bearing 18 and the outer periphery of the body 19.

Pads 34 inserted axially between the body 19 and a shoulder of the rim(not referenced) of the rear bearing. The pads 34 are made of elasticmaterial like the seal 46.

They are, for example, based on elastomer.

The pads 34 have lugs 38 for mounting them in complementary housingsbelonging to the rear bearing 16 as visible in document WO02/29958.Mechanical decoupling between stator and bearings 16, 18 is thusobtained, the resin 50 deforming elastically in radial direction.

The alternator is thus less noisy. The resin 50 allows heat to beremoved well so that the rotor, particularly the coil 62 thereof, can bemore powerful.

All this is made possible by virtue of the rectifier arrangement 1according to the invention which is able to remove more heat.

Advantageously, the electric coils 23 and/or 62 are shaped using ashaping tool which exerts force on at least one region of a coil so asto deform it. Here, the size of the coil 62 is increased, the outerperiphery thereof having a convex shape, or as an alternative a barrelshape, so that its volume is increased as is the alternator powerallowed by virtue of the arrangement 1 according to the invention.

For greater detail, reference can be made to document WO02/2958 [sic],the coils 23, 62 being mounted respectively in the notches of the body19 and on the core 67 via an insulating sheet covered with a bindingmaterial such as a polymer, advantageously of the thermoset type. Byheating, the coil 23, 62 is bound respectively to the body 23 and to thecore 67.

Pins may be used to form the coil 62. All this is possible by virtue ofthe arrangement 1.

By virtue of the invention, the alternator is more powerful and lessnoisy. Of course, the presence of the resin 50, of the pads 34 and ofthe seal 46 is not compulsory. Likewise ?[sic], as described in documentFR 01 07178 filed on May 31, 2001, the coil 62 is, as an alternative,produced by winding the conducting element over a tubular elementmounted on the core 67 which is then made in two parts; each partstarting out from one of the dishes 66, 64.

What is claimed is:
 1. Rotary electric machine of the type comprising a stator (12) with windings, a rotor (13) provided with a rotary shaft (15), a front bearing and a rear bearing on which the stator windings are fixed and in which the rotor shaft is mounted so that it can rotate, an arrangement for rectifying the current produced by the rotary electric machine, which comprises a number of positive diodes supported by a heat dissipater in the overall form of a support plate and a number of negative diodes supported by support means in the form of a plate advantageously forming part of the rear bearing, these plates being axially juxtaposed and fixed to the rear bearing, and a device providing cooling by circulating an axial stream of a cooling fluid through axial openings in said plates, at least some openings in the plate (9) supporting the positive diodes (8) being provided with a great many cooling ribs which have the shape of fins (118, 119) extending practically radially across the support plate from the radially inner edge thereof, an opening (120) for the passage of the cooling fluid advantageously being provided between each pair of adjacent fins (118, 119), characterized in that some fins (118), known as first fins, extend practically as far as the outer periphery of the plate (9) supporting the positive diodes (8).
 2. Machine according to claim 1, characterized in that at least two positive diodes (8) are arranged near the outer periphery of the plate (9) supporting the positive diodes (8), and in that other fins (119), known as second fins, extend up close to these diodes.
 3. Machine according to claim 2, characterized in that the openings (120) in the plate (9) supporting the positive diodes (8) constitute, with the adjacent fins (118, 119), channels for the accelerated flow of the cooling liquid.
 4. Machine according to claim 1, characterized in that at least a first fin (118) which extends radially as far as the outer periphery of the support plate (9) is near a positive diode (8).
 5. Machine according to claim 4, characterized in that the support plate (9) has an additional thickness in the region of the positive diode.
 6. Machine according to claim 1, characterized in that a plate (13) made of an electrically insulating material is inserted between the plates (9, 3) supporting the positive diodes (8) and is configured to allow cooling fluid to pass freely in its portion situated beneath the part of the plate (9) supporting the positive diodes (8) which has the openings (120) for the passage of the cooling air.
 7. Machine according to claim 1, characterized in that it comprises a cover part which, in the region of the fins (118, 119) of the plate (9) supporting the positive diodes (8), has corresponding radial openings. 